Array, thank you for Your fast reply.nI looked into it but I have a problem. Lets say that I have experimental acceleration data for 10 different excitation frequencies.nFor instance I choose stiffness and mass damping coefficients as my input parameters. For my output parameters I choose 10 directional accelerations amplitudes at given point (for 10 experimentally measured frequencies). So I have 2 input parameters and 10 output parameters.nNow under Parameter and Response surface optimization bar I donĀ“t seem to find a way to input my goal output accelerations that I have from the experiment. I would like to achieve that the program would find optimum combination of damping parameters that the 10 calculated acceleration at given frequencies would match my experimental accelerations (which I don t now how to input) as close as possible. nBest regards